Push bench tube die



March 27, 1934. J' R. GARNER 1,952,245

' PUSH BENCH TUBE DIE Filed March 18 1932 MTM /f//////f.

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10 I .i .9 10 l|IIl 'Ilm Il Patented Mar. 27, Ql

i UNITED STATS 1,952,245 PUSH BENCH TUBE DIE James Robert Garner,

signor of one-half' to shaman, England, a`s Howell tv Company Lim ited,Sheield', England Application March 18,

1932, Serial N0. 599,838l

In Great Britain March 31, 1931.

8 Claims.

This invention relates to dies for use in the cupping or push benchprocess of making metal tubes, its object being to provide improvementsin the construction of the dies with a view to prolonging their workinglife.

In the cupping or push bench process referred to above of making metaltubes a partially pierced heated billet is placed on the end of amandrel and forced through a die or, especially in the case of thesmaller tubes, through a succession of co-axially disposed dies.Although divided dies are known in other methods of making tubes, inthis cupping or push bench process each die has heretofore been providedin the form of a ring having a flared opening to guide the billet to theoperative drawing surface and the die is supported in an annular holderusually mounted across a suitable channel. The exterior surface of thedie and the interior surface of the holder are usually slightly bevelledor coned in order that the die may be automatically held in axialalignment with the mandrel under the pressure exerted in the process.If, as sometimes happens, the billet is torn asunder leaving a portionof the partially extruded tube gripped by a die it becomes necessary toremove each of the dies gripping the tube-remnant from its holder and tobreak it before the tube can be freed, this removal and fracture of thedies being eiiected by a Sledge hammer and taking place simultaneouslywhen, as is usual, the dies are made of cast iron.

- The present invention provides means for erfy abling such a tuberemnant to be released Without fracturing the dies which are grippingit, and also provides economical means for making the dies of the mostsuitable materials.

In the accompanying drawing:-

Figure 1 is a sectional plan of a die according to the presentinvention, the section being on the line 1-1 of Figure 2 which is anelevation of the die shown separately from its holder.

Figure 3 is a View similar to Figure l illustrating a modification. Y

Like reference numerals indicate like parts throughout the drawing.

In carrying out the present invention the die is divided radially andcomprises separate bit sectors on which the operative drawing surface 6of the die is formed and the bit sectors 10 are fitted to carriersectors 11.

The carrier sectors 11 are each formed with a groove 12 in its innersurface forming a continuous circular groove when the sectors areassembled in annular formation and the bits 10.- are held in the grooves12 of the carriers.

Preferably, the carrier sectors 11 are divided transversely to the axis,`this division being effected as shown in Figure 1 as a continuation ofone side wall of the groove 12, thereby dividing each carrier sectorinto a main part 11 surrounding the bit sector 10 and a retaining part13. The retaining'part 13 is secured to the main part 1l by means ofbolts or screws 14 and it will be understood that this `constructionprovides a convenient method of fitting the bits l0 to the carriersectors 11, 13.

The die is preferably made in three composite sectors and is supportedin the operative position by the usual annular holder 7 which isgenerally mounted across a channel or trough, not illustrated. Theexterior surfaces or perimeters of the carrier sectors 11, 13 areslightly coned as shown in Figure 1 to fit the correspondingly conedaperture 8 of the holder 7.

The complete die comprising the bits 10 and carrier sectors 11, 13 maybe assembled in the holder 7 by grouping the sectors into an annularformation with their ends abutting at 9 (as shown in Figure 2) andholding them in a loop of suitable material such asv a'strip of metaland then inserting them into the holder '7 until they are grippedthereby when the loop mayY be removed.

It is preferred to make each of the bit sectors 10 or" the same angle asits carrier sector 1l, 13, so that the ends of both the bits and thecarriers abut against one another'at the same place as indicated at 9 inFigure V2 in order to enable the die rto be moved axially along a tuberemnant without fracturing either the die or the bits.

The die will operate in the usual manner, the junctions at 9 beingsuiliciently closely fitting tov avoid scoring the tube which is beingdrawn. If the billet should be torn asunder the remnant held by one ormore of the dies may be freed therefrom by simply tapping the carriersectors 11 out of their holder 7. The die parts will then fall off thetube remnant which may be easily removed through the aperture 8 of theholder 7. Finally the die parts may be re-assembled and replaced in theholder '7 as described above so that not only is the operation offreeing the tube remnant facilitated, but the die is not destroyed inthe process.

If desired an external ange may be formed on the retaining part 13 ofeach carrier sector to over-lap the face of the holder 7.

The side Walls of the grooves 12 may be undercut and the correspondingDarts of the bits 10 may be dovetailed to fit as illustrated in Figure3. When the carrier sectors are made in two parts 11 and 13, and thedivision is situated at or between the side walls of the groove 12, itwill be appreciated that each of the bit sectors 10 may easily beinserted between the two parts of its carrier sectors before the latterare secured together. If desired, however, each carrier may be providedas a single sector and in this case the bits 10 may be threaded into theends of the grooves 12 when the latter are provided with undercut walls.

In all cases the aperture of the carrier sectors may be flared on bothsides as shown in Figure 1`.

The carrier sectors 11, 13 are preferably formed of mild steel whilstthe bit sectors 10 may be made of any suitable steel or alloy. It isgenerally preferred to make the bits and carriers separately and tol litthem into a complete annular die. If desired, however, the carriers maybe provided as a completeintegral ring which may be forged or cast witha continuous groove in its inner flared surface, and an endless bit 1,0may be cast of any desired alloy in the groove by using al suitablemould inside the carrier ring. After the exterior of the ring and, ifnecessary, the contained bit, has been machined to shape, the compositedie is divided by the desired number of radial cuts (which would berepresented by the lines 9 in Figure 2) into a number of sectors eachcontaining a bit which provides the' operative drawing surface 6.

What I claim isz- 1. In a push bench tube die, the combination ofcarrier sectors grouped-in annular formation to provide a complete ringand separate die bits shaped as ring sectors each fitted to and readilyseparable from a carrier sector of the same angle.

2. In a push bench tube die, the combination of carrier sectors, eachformed with a groove in its inner surface, means for supporting thecarriers in annular formation with their respective grooves forming onecontinuous circular groove, andV die bits in the carrier groovesseparated from one another on the sameradial planes as the carriersectors.

3. In a push bench tube die, the combination of carrier sectors groupedin annular formation to provide a complete ring and each dividedtransversely to theaxis, means for securing the parts of each carriersector together, and separate die bits held between the parts of thecarrier sectors, each die bit being formed as a sector and associatedwith one of said carrier sectors, the associated carrier sectors and diebit sectors dening similar angles and being readily separable.

4. In a push bench tube die, the combination of carrier sectors eachformed with a groove in its inner surface and divided transversely tothe axis through the groove, means for securing the parts of eachcarrier sector together, means for supporting the carrier sectors inannular formation, and die bits in the carrier grooves separated fromone another on the same radial planes as the carrier sectors.

5. In a push bench tube die, the combination of carrier sectors eachformed with a groove in its inner surface having an undercut Wall, andeach divided transversely to the axis in a continuation of one wall ofthe groove therein, means for securing the parts of each carrier sectortogether, means for supporting the carriers in annular formation withtheir respective grooves forming one continuous undercut circulargroove, and die bits with tapered sides iitting the carrier grooves andseparated from one another on the same radial planes as the carriersectors, substantially as specied.

6. In a push bench tube die, the combination with a holder having anaxially tapered aperture, carrier sectors arranged in annular formationto provide a complete ring and having axially tapered peripheralsurfaces conforming substantially to the aperture in the holder, andseparate bits on which the operative drawing surface of each die isformed, each of said bits being fitted to and supported by one of saidcarrier sectors and being readily separable therefrom.

7. In a push bench tube die, the combination with a holder having anaxially tapered aperture, carrier sectors arranged in annular formationand having axially tapered peripheral surfaces conforming substantiallyto the aperture` in the holder, and separate bits on which the operativedrawing surface of each die is formed, each oi said bits being fittedand supported by one of said carrier sectors, each of said carriersectors being formed in two sectons separated transversely of the axisof the die, and means for connecting the sections of each sector toclamp the associated bit therebetween.

8. In a push bench tube die, the combination of carrier sectors, eachformed with an undercut groove in its inner surface, means forsupporting the carriers in annular formation with their respectivegrooves forming one continuous circular groove, and die bits withtapered sides` fitting. the carrier grooves and separated from oneanother on the same radial planes as the carrier sectors.

JAMES ROBERT GARNER.

